* Re: PATCH: Work in progress cleaning shrink_mmap
2000-05-15 3:04 PATCH: Work in progress cleaning shrink_mmap Juan J. Quintela
@ 2000-05-15 3:06 ` Juan J. Quintela
2000-05-15 15:21 ` Tigran Aivazian
0 siblings, 1 reply; 4+ messages in thread
From: Juan J. Quintela @ 2000-05-15 3:06 UTC (permalink / raw)
To: linux-mm
>>>>> "juan" == Juan J Quintela <quintela@fi.udc.es> writes:
Hi
I forget to send the patch the first time.
juan> Well, that have been my findings to the moment. Any comments about
juan> the patch of my findings are welcome.
Later, Juan.
diff -urN --exclude-from=/home/lfcia/quintela/work/kernel/exclude pre9-1/include/linux/swap.h testing/include/linux/swap.h
--- pre9-1/include/linux/swap.h Sun May 14 20:20:53 2000
+++ testing/include/linux/swap.h Mon May 15 01:50:46 2000
@@ -163,11 +163,16 @@
/*
* Helper macros for lru_pages handling.
*/
-#define lru_cache_add(page) \
+#define __lru_cache_add(page) \
do { \
- spin_lock(&pagemap_lru_lock); \
list_add(&(page)->lru, &lru_cache); \
nr_lru_pages++; \
+} while (0)
+
+#define lru_cache_add(page) \
+do { \
+ spin_lock(&pagemap_lru_lock); \
+ __lru_cache_add(page); \
spin_unlock(&pagemap_lru_lock); \
} while (0)
diff -urN --exclude-from=/home/lfcia/quintela/work/kernel/exclude pre9-1/mm/filemap.c testing/mm/filemap.c
--- pre9-1/mm/filemap.c Fri May 12 23:46:46 2000
+++ testing/mm/filemap.c Mon May 15 04:47:04 2000
@@ -244,41 +244,41 @@
spin_unlock(&pagecache_lock);
}
+/**
+ * shrink_mmap - Tries to free memory
+ * @priority: how hard we will try to free pages (0 hardest)
+ * @gfp_mask: Restrictions to free pages
+ *
+ * Put something Here
+ */
+
int shrink_mmap(int priority, int gfp_mask)
{
- int ret = 0, count;
- LIST_HEAD(old);
- struct list_head * page_lru, * dispose;
+ int count;
+ struct list_head * page_lru;
struct page * page = NULL;
count = nr_lru_pages / (priority + 1);
/* we need pagemap_lru_lock for list_del() ... subtle code below */
spin_lock(&pagemap_lru_lock);
- while (count > 0 && (page_lru = lru_cache.prev) != &lru_cache) {
+ page_lru = lru_cache.prev;
+ while (count > 0 && (page_lru != &lru_cache)) {
page = list_entry(page_lru, struct page, lru);
- list_del(page_lru);
- dispose = &lru_cache;
- if (PageTestandClearReferenced(page))
+ /*
+ * We clear the referenced bit and move the page to
+ * the end of the LRU list
+ */
+ if (PageTestandClearReferenced(page)) {
+ __lru_cache_del(page);
+ __lru_cache_add(page);
goto dispose_continue;
+ }
count--;
/*
- * I'm ambivalent on this one.. Should we try to
- * maintain LRU on the LRU list, and put pages that
- * are old at the end of the queue, even if that
- * means that we'll re-scan then again soon and
- * often waste CPU time? Or should be just let any
- * pages we do not want to touch now for one reason
- * or another percolate to be "young"?
- *
- dispose = &old;
- *
- */
-
- /*
* Avoid unscalable SMP locking for pages we can
* immediate tell are untouchable..
*/
@@ -288,11 +288,12 @@
if (TryLockPage(page))
goto dispose_continue;
- /* Release the pagemap_lru lock even if the page is not yet
- queued in any lru queue since we have just locked down
- the page so nobody else may SMP race with us running
- a lru_cache_del() (lru_cache_del() always run with the
- page locked down ;). */
+ /*
+ * Release the pagemap_lru lock since we have just
+ * locked down the page so nobody else may SMP race
+ * with us running a lru_cache_del() (lru_cache_del()
+ * always run with the page locked down ;).
+ */
spin_unlock(&pagemap_lru_lock);
/* avoid freeing the page while it's locked */
@@ -312,10 +313,13 @@
}
}
- /* Take the pagecache_lock spinlock held to avoid
- other tasks to notice the page while we are looking at its
- page count. If it's a pagecache-page we'll free it
- in one atomic transaction after checking its page count. */
+ /*
+ * Take the pagecache_lock spinlock held to avoid
+ * other tasks to notice the page while we are
+ * looking at its page count. If it's a
+ * pagecache-page we'll free it in one atomic
+ * transaction after checking its page count.
+ */
spin_lock(&pagecache_lock);
/*
@@ -328,7 +332,7 @@
/*
* Is it a page swap page? If so, we want to
* drop it if it is no longer used, even if it
- * were to be marked referenced..
+ * were to be marked referenced.
*/
if (PageSwapCache(page)) {
spin_unlock(&pagecache_lock);
@@ -362,26 +366,19 @@
UnlockPage(page);
page_cache_release(page);
dispose_continue:
- list_add(page_lru, dispose);
+ page_lru = page_lru->prev;
}
- goto out;
+ spin_unlock(&pagemap_lru_lock);
+
+ return 0;
made_inode_progress:
page_cache_release(page);
made_buffer_progress:
+ lru_cache_del(page);
UnlockPage(page);
page_cache_release(page);
- ret = 1;
- spin_lock(&pagemap_lru_lock);
- /* nr_lru_pages needs the spinlock */
- nr_lru_pages--;
-
-out:
- list_splice(&old, lru_cache.prev);
-
- spin_unlock(&pagemap_lru_lock);
-
- return ret;
+ return 1;
}
static inline struct page * __find_page_nolock(struct address_space *mapping, unsigned long offset, struct page *page)
diff -urN --exclude-from=/home/lfcia/quintela/work/kernel/exclude pre9-1/mm/vmscan.c testing/mm/vmscan.c
--- pre9-1/mm/vmscan.c Sun May 14 00:58:25 2000
+++ testing/mm/vmscan.c Mon May 15 04:47:12 2000
@@ -429,12 +429,13 @@
* Don't try _too_ hard, though. We don't want to have bad
* latency.
*/
-#define FREE_COUNT 8
-#define SWAP_COUNT 8
+#define FREE_COUNT 16
+#define SWAP_COUNT 16
static int do_try_to_free_pages(unsigned int gfp_mask)
{
int priority;
int count = FREE_COUNT;
+ int swap_count;
/* Always trim SLAB caches when memory gets low. */
kmem_cache_reap(gfp_mask);
@@ -470,12 +471,11 @@
* This will not actually free any pages (they get
* put in the swap cache), so we must not count this
* as a "count" success.
- */
- {
- int swap_count = SWAP_COUNT;
- while (swap_out(priority, gfp_mask))
- if (--swap_count < 0)
- break;
+ */
+ swap_count = SWAP_COUNT;
+ while (swap_out(priority, gfp_mask)) {
+ if (--swap_count < 0)
+ break;
}
} while (--priority >= 0);
--
In theory, practice and theory are the same, but in practice they
are different -- Larry McVoy
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